Response criteria for the therapeutic efficacy of treatments for benign prostatic hyperplasia (BPH) were proposed following the International Consultation on BPH held in 1993. In the present study, we validated the criteria and proposed a simplified form, which consists of the responses of three parameters: symptom score and quality of life assessed by the international prostate symptom score and the maximum flow rate. Each of the three individual parameters is evaluated as one of four response grades: excellent, good, fair or poor, and the number of response grade of the three parameters determines the overall response. Excellent and Good responses are regarded as effective, and fair and poor are regarded as not effective. The validity of the response criteria was assessed by comparing the responses determined by these criteria with those made by physicians in charge using a group of 225 patients receiving various treatments. The agreement rates on effectiveness of overall responses between the response criteria and physicians were 77% for a multicenter trial of medical treatment (n = 94), 100% for TURP (n = 23), 92% for laser treatment (n = 47), 80% for thermal treatment (n = 26) and 78% for alpha-blockers (n = 35), respectively. Altogether, 88% (198 of 225 cases) were evaluated accurately regarding effectiveness. Addition of prostate volume to the battery of response parameters made little contribution to diagnostic accuracy. Deletion of any of the other three parameters, however, significantly compromised the quality of assessment. These results suggest that the proposed criteria may be useful as the standard method for the assessment of the clinical efficacy of BPH treatment.